Questions tagged [orbital-elements]

Orbital elements are a set of parameters that uniquely identify a specific orbit.

Filter by
Sorted by
Tagged with
5
votes
0answers
53 views

Poincaré map of orbital trajectories

A Poincaré map, by definition, is supposed to be a reduction of a phase diagram on a codimensional plane cutting normal to the original trajectory. In this form, one should plot points from the phase ...
3
votes
0answers
22 views

Mean to Osculating conversion for non-J2 averaged elements

What is the appropriate technique to convert mean elements (true anomaly averaged) into osculating elements when the model has J2, SRP, drag and additional forces modeled. Brouwer's transformation is ...
0
votes
0answers
18 views

How can I convert a Walker constellation (i: t/p/f) to cartesian position and velocity coordinates (ECI)?

I need to convert a Walker constellation (i: t/p/f) to cartesian position and velocity coordinates relative to earth center (ECI) -- i.e., position x,y,z and velocity x,y,z. Standard Anaconda Python ...
1
vote
1answer
53 views

How frequent do TLEs of LEO satellites change?

I was doing some MATLAB simulations on LEO satellites using TLEs obtained from n2yo websites and I observed that n2yo was displaying a different TLE for the same satellite after a few days. I don't ...
3
votes
0answers
30 views

How do I calculate the change in the argument of periapsis after a plane change maneuver?

Let's say I have a spacecraft in an initial geocentric orbit with the following parameters: a = 7,960,000 m, e = 0.010, $\Omega$ = 180$^{\circ}$, i = 98$^{\circ}$, $\omega$ = 90$^{\circ}$, $\theta_0$ =...
2
votes
1answer
50 views

Calculating orbital parameters for given requirements

I'm trying to determine what's the best way to calculate the required orbit for a LEO remote sensing satellite. I understand there exists the trade-off between sensor coverage and sensor accuracy, but ...
2
votes
1answer
118 views

Argument of Perigee for a circular orbit

For a perfectly circular orbit (e=0), how is the argument of perigee defined?? Thanks.
4
votes
2answers
104 views

Where can I find examples of orbital state vectors?

I'm currently trying to write a program that can calculate orbital trajectories. The goal is to take any orbital state vector (position, velocity) and convert it into Keplerian orbital elements, or ...
13
votes
2answers
740 views

Can the Right Ascension and Argument of Perigee of a spacecraft's orbit keep varying by themselves with time?

I came across the orbital data for a low Earth orbit spacecraft and one thing which I am not able to understand is why does its Right Ascension of ascending node and Argument of Perigee keep changing ...
1
vote
2answers
110 views

Finding Earth-Centered Coordinates of Periapsis

I am currently writing a program that accepts a state vector, calculates the corresponding Keplerian ellipse, and then draws the ellipse. But I'm stuck at the following point. I currently need some ...
3
votes
1answer
74 views

How to calculate angle in elliptic orbit?

I would like calculate angle in elliptic orbit ZCP at any time, where: Z (position of periapsis), C (center of ellipse), P (current position of planet). I find topic, where is picture (in accepted ...
2
votes
1answer
105 views

True Anomaly of Circular Orbit

How would you calculate the true anomaly of a circular orbit (e=0)? I'm trying to design an orbit for a mission on STK and so I'm not sure what the eccentric anomaly (in order to calculate true ...
2
votes
0answers
66 views

Compute heliocentric ecliptic coordinates from Kepler's laws

I'm writing a program to compute the heliocentric ecliptic position of planets and asteroids. I want to output rectangular coordinates oriented according to the ecliptic: positive X in the direction ...
2
votes
0answers
94 views
3
votes
1answer
50 views

How to obtain the initial positions and velocities of an inclined orbit?

I have (x,y,z) initial positions and (vx,vy,vz) initial velocities in a coplanar orbit with respect to the reference frame. If I change the inclination of this orbit with the angle i, how I can ...
1
vote
0answers
50 views

How to get true anomaly using subsatellite point (latitude)?

I am working on an application which is using an orbit propagator. I have a satellite which sets its latitude using this orbit propagator. I want to change the latitude of the satellite by a new value,...
1
vote
0answers
85 views

What is wrong with my orbit sim equations? How can I fix them?

Edit: Partial question: The object now moves in an ellipse like it's supposed to, but it orbits around a different point than I intend. How can I make it orbit around a particular object at a point? ...
4
votes
1answer
87 views

Is software available for writing two line element files from Keplerian elements?

I am interested in writing a TLE file from existing Keplerian elements. Is software available on the web to do this?
2
votes
1answer
121 views

NAIF and SpiceyPy returning seemingly inaccurate results

I am yet another amateur astrophysics enthusiast creating a solar system simulator. I began by hard-coding planetary bodies and their satellite orbiting characteristics via JPL data tables such as ...
2
votes
0answers
33 views

Help needed with obtaining position vector of Spacecraft in Heliocentric-Ecliptic frame

I have been now using the ephemeris table attached as an image. It gives the orbital elements of all planets on Jan 1 2000 calculated from Heliocentric-Ecliptic frame. The current planetary orbital ...
8
votes
1answer
213 views

Deviation of semi-major axis

If I calculate the semi-major axis of Molniya-1T with $a = \sqrt[3]{\dfrac{GM}{n^2}}$ with $n=3.18683728\text{ }d^{-1}$, I get another apoapsis ($a=19505.7$ km) as noted at Heavens Above: apogee ...
3
votes
1answer
55 views

Generating JPL HORIZONS parameters for use with JPL HORIZONS itself

I want to be able to calculate RA/Dec for a given body with JPL HORIZONS, using a heliocentric specification of the orbital elements for a small solar system body (say, Apophis), but instead of using ...
3
votes
1answer
113 views

Simulating a nanosatellite lunar flyby

I am trying to create a Lunar Flyby mission for small nanosatellites and I want to plot an orbit for it. The problem is that no website has proper information as to what variables, problems and ...
1
vote
1answer
80 views

TA of the intersection of 2 orbits with different AoP

Two orbits are given with the same orbital elements, except the argument of perigee (AoP). How to calculate the true anomaly (TA) of the intersection of the orbits? Currently, I calculate it ...
1
vote
1answer
223 views

How accurate can a satellite's orbit be?

How precise can an artificial satellite be when it comes to following the exact orbit in relation to Earth or hitting the same point above Earth in orbit? Which orbit would be the most stable for this?...
3
votes
1answer
157 views

What are common guidance strategies for a finite orbital maneuver?

Suppose we have our spacecraft in a circular orbit around the Moon and we want to transfer it to an elliptic orbit with a medium-thrust (10-100N) retrograde burn. Based on the current state estimate, ...
1
vote
0answers
58 views

Calculating t(E)

The mean radius vector of an elliptic orbit is equivalent to the semi-major axis. If I sample the radius vector of an unperturbed elliptic orbit as a function of the eccentric anomaly with at a ...
0
votes
0answers
265 views

How can I calculate Mean anomaly from True longitude?

So, I have - TLE data - Reference frame: QMOD - Type: Osculating - Semimajor axis - Eccentricity - Asceding node - ...
2
votes
1answer
72 views

Comparison of AOP change of the orbits

I'm comparing how the Argument of perigee (AOP) changes for 2 orbits (O1 and O2). The orbits ...
2
votes
1answer
257 views

different ways to calculate satellite height

I found 2 formulas for calculating height. First is: height = magnitude(satillate_position_vector) - Earth_radius Second is: ...
1
vote
0answers
397 views

computing radial, along track, cross track components (differences) from two ECEF coordinates and velocities [closed]

I need to compute radial, along track, cross track components (differences) for two points in the orbital planes. I found the unit vectors of radial, along track, cross track but couldn't sure how ...
6
votes
2answers
355 views

Is it possible to plot the ground track of a satellite with just azimuth & elevation angles without range?

I came across this question on StackOverflow about Satellite Trajectory plot. In the code mentioned in the question, the user takes only the Azimuth & Elevation angles (radians) & converts ...
4
votes
1answer
488 views

How to calculate the orbital distance between 2 satellites given the TLEs

I have 2 LEO satellites with the same orbital plane with same inclination & longitude of the ascending node. I have the TLEs for each satellite. How do I calculate the orbital distance between the ...
3
votes
1answer
106 views

What is the angle between two orbits in the equatorial plane?

My orbit is in the equatorial plane. When i apply thrust in the y or x axis, it rotates around the focus or planet - see red and blue orbit in the image below. I know the the semi-major-axis and ...
1
vote
0answers
255 views

Need help with calculating state vectors from Orbital Elements - C#

I have been working on a project where I want to visualize the orbits in the solar system with the help of Unity Engine. I have been using different guides and similar questions on this forum to ...
5
votes
2answers
995 views

What is hyperbolic eccentric anomaly F?

I have no idea what this is and have been searching on the net but all I get is eccentric anomaly. The equation that relates hyperbolic eccentric anomaly F to its true anomaly $\theta$ is exactly the ...
3
votes
0answers
55 views

GMAT starts simulating in 1990, how do I change that?

I'm running a simulation of a few satellites using their TLE epochs and other orbital parameters. GMAT gives the correct dates when writing the report output, but the contact locator and spacecraft ...
3
votes
1answer
105 views

What are the symbol definitions in the equations for finding orbital elements?

I've been looking at the answer to this question on how to convert position and velocity to orbital elements, but some of the symbols are not defined and there are no reference links for those symbols....
4
votes
1answer
218 views

How to determine the optimal orbit for a LEO satellite

Our goal is to determine the best orbit that will allow a ground station (so this is a fixed point on earth) to communicate a maximum number of times par day with a LEO satellite. So the question is :...
4
votes
1answer
887 views

TLE SGP4 Coordinate Transformations

I am working on developing a user friendly SGP4 orbit propagator in C on a PIC24. I have extensively read Revisiting Spacetrack Report #3 and celestrak - there are a few outstanding questions I have....
5
votes
1answer
111 views

simple example applying perturbed effect on orbit propogation?

I need to apply perturbation effect to orbit propagation. I am programmer not a physicist. I’ve already wrote program to propagate not perturbation orbit and show satellite ground track. So I know how ...
0
votes
1answer
935 views

TLE data conversion to osculating orbit elements [closed]

I got the latest TLE from www.celestrak.com for a satellite. How could I convert it to osculating elements? Please, share some links/references.
1
vote
2answers
699 views

How to get velocity vector from GPS NMEA data?

I am writing a program to receive and interpret NMEA data from a GPS receiver. I am working with an Adafruit Ultimate GPS Receiver integrated with an Arduino. The $GPRMC NMEA Sentence contains the ...
1
vote
1answer
553 views

Help with Cartesian State Vectors → Keplerian Orbit Elements C#

EDIT I am currently attempting to try the standard Cartesian State Vectors to Keplerian Orbit Elements conversion but i am having problems getting my head around the formulas and the use of vectors. ...
0
votes
1answer
2k views

Algorithm to convert from ECEF coordinates to ECI coordinates

I am looking for an Algorithm (the formulas; not the code) to convert from ECEF coordinates to ECI coordinates. I have a MATLAB code for it but am unable to understand certain things. So it'd be ...
1
vote
1answer
61 views

Applying secondary orbital perturbation effects

I read about secondary effects which influence on orbit propagation like solar radiation, moon, etc. (https://en.wikipedia.org/wiki/Orbit_modeling). First I calculate position vector Rpqw to object (...
11
votes
2answers
970 views

Why is the sidereal period of the Earth 362.392667 days?

Using JPL's Horizons API I can look at the orbital elements for the EM Barycenter wrt the Solar System Barycenter at J2000. The output looks like this: Watch for the PR (Sidereal orbit period) ...
4
votes
0answers
245 views

Ecliptic reference frame for satellite orbits in JPL Horizons

I'm trying to get orbital elements for natural satellites of all the plates with respect to their system's barycenters and I don't see how it is possible that using the ecliptic as a reference plane ...
2
votes
0answers
401 views

Clarify algorithm finding satellite ground track and orbit position

I try to plot satellite ground track. I found lots of formulas but hardly find algorithm which describe how to uses them one-by-one and step-by-step. As I understand the algorithm will be: 1) Get ...
5
votes
0answers
126 views

Locally optimal control for low thrust transfers with J2 and other Earth perturbations

Background As detailed in this answer low thrust optimization is subject of ongoing research. There are a few closed-loop control laws which allow to achieve a locally optimal (but close to globally ...